Method and apparatus for descaling strip material, especially strip iron



Oct. 5, 1965 R. AMTMANN 3,209,429

METHOD AND APPARATUS FOR DESCALING STRIP MATERIAL, ESPECIALLY STRIP IRON Original Filed Feb. 17, 1958 6 Sheets-Sheet 1 FIG.

Wyn/70 RadaZ I I94 fag Oct. 5, 1965 R. AMTMANN METHOD AND APPAR ATUS FOR DESGALING STRIP MATERIAL, ESPECIALLY STRIP IRON Original Filed Feb. 17, 1958 6 Sheets-Sheet 2 ftfidfi Oct. 5, 1965 R. AMTMANN METHOD AND APPARATUS FOR DESCALING STRIP MATERIAL, ESPECIALLY STRIP IRON Original Filed Feb. 17, 1958 6 Sheets-Sheet 3 AMTMANN 3,209,429 ARATU FOR DESCALING STRIP ESPECIALLY STRIP IRON Oct. 5, 1965 METHOD A MAT R ND APP ERIAL, Original Filed Feb. 17, 1958 6 Sheets-Sheet 4 1965 R. AMTMANN METHOD TUS FOR DESCALING STRIP MA PECIALLY STRIP IRON Original Filed Feb. 17, 1958 AND APPARA TERIAL, ES

6 Sheets-Sheet 5 O 1965 R. AMTMANN 3,209,429

METHOD AND APPARATUS FOR DESGALING STRIP MATERIAL, ESPECIALLY STRIP IRON Original Filed Feb. 17, 1958 6 Sheets-Sheet 6 INVENTOR Rad/eff firm/ mam WWW ATTORNEY United States Patent 3,209,429 METHOD Al\lD APPARATUS FOR DESCALING STRIP MATERIAL, ESPECIALLY STRIP IRON Rudolf Amtmann, Hemer, Westphalia, Germany, assignor to Masehinenfabrik August Seuthe, Hemer, Westphalia, Germany Original application Feb. 17, 1958, Ser. No. 715,666, new Patent No. 3,054,162, dated Sept. 18, 1962. Divided and this application July 19, 1962, Ser. No. 210,953 Claims priority, application Germany, Feb. 16, 1957, M 33,268 Claims. (Cl. 2981) The present application is a divisional application of my 'copending application Serial No. 715,666 filed February 17, 1958, now Patent No. 3,054,162.

The invention relates to an apparatus for continuously descaling strip material and especially strip iron, in which the strip is drawn in zig-zag fashion over deflecting rollers and mutually displaced and adjustable metal guide bars with curved guide surfaces, and the scale is detached by the guide bars engaging in the vertex of a bending angle formed by the strip.

The invention is based on a former suggestion of the applicant, according to which the strip materials is drawn in zig-zag fashion over deflecting rollers and mutually displaced and adjustable metal guide bars with curved guide surfaces. The strip is passed over each guide bar at a bending angle which is preferably between 60 and 120. The scale is thereby detached from the surface of the strip by the guide bar arranged in the vertex of the bending angle, a portion of crushed scale being drawn between the bar and the strip to serve as lubricant, for the subsequent removal of which brushes are provided.

An object of the present invention is to provide an apparatus for continuously descaling strip material, particularly strip iron, which comprises in the region of the curved guide surface of each guide bar at least one pastage extending substantially perpendicularly to the surface of the strip for feeding the pressure water between the guide bar and the surface of the strip. In order, particularly in the case of relatively wide strips, to obtain as far as possible a pressure water cushion of uniform configuration over the entire width of the strip, it is advisable to equip each guide bar with several feed passages distributed over its length, which passages are connected to a common feed conduit for the pressure water. The feed passages are preferably constructed as nozzles and arranged with their axes in the longitudinal central plane of the guide bar, so that the strip is flushed with water jets projected with great force, practically over its entire width, and the scale detached from the surface of the strip by bending the strip is flushed out of the pores of the strip and washed away. The mouths of the nozzles are preferably widened in fan-shape in the longitudinal direction of the guide bars so that, to obtain the same descaling effect, a smaller number of nozzles is required.

In another form of construction the apparatus according to the invention is provided with at least one elongated pressure water chamber extending in the longitudinal direction of the guide bar, which pressure water chamber is open toward the guide surface of the bar and connected to a pressure water feed conduit. In order to obtain a uniform distribution of pressure water on the entire width of the strip, it is preferable to provide several pressure water chambers arranged one behind the other in the longitudinal direction of each guide bar, which chambers extend over a considerable portion of the width of the strip and are connected by short connection passages to a distributor passage of relatively large cross section arranged under the guide bar and extending in the longitudinal direction thereof.

With the aid of the invention metal strips with a very 3,209,429 Patented Get. 5, 1965 Wide range of thicknesses, for example strip iron from about 0.5 to 10 and even more mms. in thickness can be descaled. The size of the bending angle depends upon the material and the thickness can be descaled. The size of the bending angle depends upon the material and the thickness of the strip, and also upon the thickness and composition of the layer of scale. In most cases the most favorable bending angle lies between about 60 and but deviations from these values are conceivable.

Several preferred embodiments of the invention are illustrated by way of example in the accompanying drawings, in which:

FIG. 1 is a diagram showing the general layout of a descaling apparatus according to the invention;

FIGS. 2 and 3 are vertical central sections showing the descaling apparatus in greater detail, FIG. 2 showing a first portion and FIG. 3 a section portion of the apparatus arranged at the left side of the portion shown in FIG. 2;

FIG. 4 is a cross section through a guide bar equipped with pressure water nozzles;

FIG. 5 is a top plan view of FIG. 4;

FIG. 6 is a cross section showing half of a modified guide bar equipped with pressure water chambers; and

FIG. 7 is a top plan view of the complete embodiment shown partly in FIG. 6.

FIGS. 7 and 8 are longitudinal cross sections through the bending devices shown in FIGS. 5 and 7 respectively and illustrate more clearly the arrangement of the mouth ends 11a of the nozzles shown in FIG. 5 and the grooves 26 and 27 in the bending device of FIG. 7.

Referring now more particularly to the drawings, FIG. 1 shows a descaling apparatus in which a strip of band iron 1 running off a reel, not shown in the drawings, is first passed through a braking device 2 composed of four mutually adjustable rollers. By adjustment of the rollers of the braking device 2 in the directions x-x, the tractional resistance of the strip can be regulated. A dressing or straightening mechanism which is not driven can, for example, also be used as braking device. An upper roller 2a of the braking device 2 serves at the same time as guiding and deflecting roller for the strip 1 which is subsequently passed in zig-zag fashion over a guide bar 3 which is detachably mounted on a carrier 4 adjustable in the directions yy The guide bar 3, as can be seen from FIGS. 1 and 4, engages the surface of the strip in the vertex of the bending angle a formed by the strip 1. The size of the bending angle a depends partly upon the material of the strip to be descaled, the thickness of the strip and also the composition and thickness of the scale layer and generally lies between 60 and 120 in the case of iron strip about 1 to 10 mms. in thickness. By adjustment of the carrier 4 in the directions y-y the bending angle of the strip 1 can be adjusted within a range of, for example, about 60 to The bending angle a is changed when a strip of a different thickness and/or with a different scale composition is to be passed through the descaling apparatus.

Beyond the guide bar 3 engaging the under side of the strip in FIG. 1, the strip 1 is again deflected by a roller 5 and then runs through a pulling device 6, which, in the example illustrated in FIG. 1, consists of two rollers at least one of which is driven and which are mutually adjustable in the directions zz By change of the spacing and the speed of rotation of the rollers mounted in the pulling device 6, the tensional force imparted to the band 1 can be regulated. Beyond the pulling device 6, the strip 1 is preferably guided over another deflecting roller 7 and subsequently over a second guide bar 3a displaced in relation thereto, which bar engages the upper side of the strip. By the guide bar 3a the strip 1 is bent in zig-zag fashion in the opposite direction, the bending angle 0: formed at the guide bar 3a being of the same dimension as the bending angle or at the guide bar 3. The guide bar 3a is, just like the guide bar 3, exchangeably mounted on a carrier 4a adjustable in the directions yy Beyond the guide bar 3a the strip is returned into the horizontal plane of travel of the strip by a deflecting roller 8 and subsequently runs through a second pulling device 9 which, like the pulling devices 6, consists of rollers adjustable in relation to each other in the directions zz at least one of said rollers being driven at an adjustable speed of rotation.

In the descaling apparatus illustrated in FIGS. 2 and 3, the first guide bar 3, contrary to the arrangement shown in FIG. 1, is arranged above the strip 1, whereas the second guide bar 3a shown in FIG. 3 is below the strip. It is immaterial whether the arrangement according to FIG. 1 or that according to FIGS. 2 and 3 is chosen. As can be seen from FIG. 2 the strip 1, in entering the apparatus, first passes between a pair of feed-in rollers 33, at least one of which is driven. These feed-in rollers are followed by the rollers of the braking device 2. In the present case five rollers are provided some of which are braked directly or on their ends. These rollers also serve for straightening the strip. Means for braking the rollers of the braking device are indicated at 34. The braking force can be adjusted by spring pressure. The strip 1 passes from the braking device 2 into a first descaling unit 35 of the apparatus in which the strip is guided over rollers 36 and 5. The guide bar 3 is arranged between these rollers 36 and and is adjustable in vertical direction by means of a screw 37. The rollers 36 and 5 can be adjusted in vertical direction with the aid of screws 38. A rotary brush 19 is mounted above the roller 5 and driven by a motor 88. After the removal of scale on one side of the strip 1, the latter passes from the descaling unit 35 into the pulling device 6 which has driven rollers 39 around which the strip is passed so as to be pulled through the unit 35 against the resistance of the braking device 2.

For descaling the other side of the strip 1, the strip travels first through another braking device 40 following the pulling device 6 and corresponding substantially to the braking device 2. As shown in FIG. 3, the strip 1 then enters a second descaling unit 41 of the apparatus in which the guide bar 3a is arranged. This guide bar 3a is located between guide rollers 42 and 8. A rotary brush 20 is coordinated to the roller 8 and driven by a motor 43. Two further units 44 and 45 are connected up in series beyond the second descaling unit 41. The units 44 and 45 include driven brushes 46 and 47 which cooperate with adjustable guide rollers 48 and 49 respectively. Spraying devices 50 are provided for supplying water under sufficiently high pressure to each of the brushes 46 and 47. These spraying devices can be coordinated to the upper and lower sides of the strip. Nozzles for spraying water under pressure are also coordinated to the already mentioned guide bars 3 and 3a. The special forms of construction and arrangement will be hereinafter described. Beyond the unit 45 the pulling device 9 is provided which corresponds in construction to the pulling device 6 of FIG. 2.

As can be seen from FIGS. 4 and 6, the guide bar 3 has a curved guide surface 10. This guide surface is cambered according to a radius r which is differently dimensioned in guide bars serving for descaling strips of different thicknesses. It has been found advantageous to make the radius 1' about four times as great as the actual thickness s of the strip.

In the form of construction of the descaling apparatus illustrated in FIGS. 4 and 5, the guide bar 3 and the similarly constructed guide bar 3a are provided with several nozzles or jets 11 arranged at regular intervals apart in the longitudinal direction of the bar, through which nozzles water under high pressure of about 30 to 100 atms. for example, can be fed between the guide surface 10 and the surface of the strip. The nozzles 11 are arranged with their axes in the longitudinal central plane a-a of the guide bar 3. These nozzles 11 are connected by means of short passages 12 to a distributor passage 13 of relatively large cross section passing through the guide bar over its entire length and extending parallel to the guide surface 10. The distributor passage 13 is, as can be seen from FIG. 5, connected at both ends to a feed conduit 14 and 14a respectively for the pressure water. The pressure water is fed to the guide bars 3, 3a preferably by a high-pressure pump which is not shown on the drawings but which is so constructed that the pressure and quantity of the water fed can be regulated, preferably continuously, within wide limits. It is evident that it is also possible to provide for the regulation of the pressure and/ or the quantity of water fed to the nozzles 11 of the guide bars 3, 3a, throttle elements fitted in the feed conduit 14, 14a.

As shown in FIG. 5, the nozzles 11 arranged one behind the other in the longitudinal direction of the guide bar 3, are uniformly distributed over a range corresponding to the total width b of the strip 1, so that a uniform layer of pressure water forms over the entire width of the strip between the guide surface 10 and the surface of the strip 1. As can be seen from FIG. 5, the nozzles 11 have their mouths or outlet openings 11a widened in fan-fashion in the longitudinal direction of the guide bars 3, 3a, whereby the mouths 11a of adjacent nozzles merge with each other. As a result the jets of pressure water passing out of the nozzles 11 at a high speed spread in fan-fashion in the longitudinal direction of the guide bars 3 and 3a respectively, so that, even if adjacent nozzles 11 are spaced apart at relatively wide spaces 6, the whole width b of the strip is sprayed with water jets emerging with a considerable amount of kinetic energy. The pressure water fed by the nozzles 11 forms between the curved guide surface 10 and the surface of the strip 1 facing this guide surface, a pressure water cushion by which the strip is lifted off the guide surface 10. The water flows olf laterally on both sides of the guide surface 10 in the direction w-w and perpendicularly thereto.

In the embodiment illustrated in FIGS. 4 and 5, the guide bar 3 is exchangeably fixed on the carrier 4 by bolts 15. Thus, the guide bar can be easily exchanged when strips of different materials, different thicknesses, different widths and with different scale formations are to be descaled.

In the construction illustrated in FIGS. 6 and 7, the guide bar 3 is composed of two complementary bending members of sections 3 and 3 being divided along a plane extending parallel to the longitudinal central plane aa, which sections are clamped between jaws 23, 24. The clamping jaws 23, 24 are drawn together by screws 25. The facing contact surfaces of the guide bar sections 3 and 3 are ground and when in clamped position are pressed tightly one against the other by the jaws 23, 24. It is evident that it is also possible to provide packings between the contacting surfaces of the guide bars 3 and 3 In the crest or apex of the curved guide surface 10 two elongated pressure water chambers 26, 26a are arranged one behind the other in the longitudinal direction of the guide bar 3. These pressure Water chambers 26, 26a are open toward the respective guide or bending surface 10, reach to the full height of the guide bar 3 and together extend over about three-quarters of the strip width. The division plane of the guide bar 3 coincides with one of the longitudinal walls of the pressure water chambers 26, 26a. On both sides of the pressure water chambers 26, 26a the crown of the guide bar 3 is provided with a longitudinal groove 27 corresponding approximately to the width of the chambers, which groove is only shallow, being eg about 2 mms. in depth. With the aid of this shallow longitudinal groove a uniform pressure water cushion is formed at the crown of the guide bar 3 on each side of the pressure water chambers 26, 26a so that the scale will be washed away on both sides in the longitudinal direction of the guide bar.

The pressure water chambers 26, 26a are each connected by two passages 28, 28a provided in the clamping jaw 24 to a distributor passage 29 of relatively large cross section extending through the clamping jaw 24 in the longitudinal direction of the guide bar 3. The distributor passage 29, as in the embodiment illustrated in FIGS. 4 and 5, is connected at both ends to pressure water feed conduits 14, 14a.

As shown particularly in FIG. 1, but also in FIGS. 2 and 3, each of the guide bars 3 and 3a is followed by a spraying device 16 and 16a respectively, provided with a plurality of nozzles distributed over the width b of the strip and by which the surface of the strip actually descaled is again sprayed with jets of water under high pressure. Such a spraying device 16 or 16a can obviously also be used when the guide bars are constructed as in the embodiments illustrated in FIGS. 6 and 7. The nozzles of the spraying device 16 or 16a, which are not shown in detail in FIGS. 1 to 3, are connected by a common distributor pipe and by a connection conduit 17 or 17a thereon, to a Water feed conduit 18 or 18a leading to a high pressure pump, not shown in the drawings, like the connection conduits 14, 14a of the nozzles 11 or the chambers 26, 2611, or the distributor pipes 30, 30a.

The strip 1, after passing the spraying device 16 or 16a, is fed between at least one deflecting roller 5 or 3 and a brush 19 or 20 respectively. The brushes 19, 20 engage the descaled surface of the strip sprayed by the preceding spraying device 16 or 16a and are adjustable in the direction tt Approximately tangential to the periphery of the brushes 19 and 20 respectively one or more adjustable nozzles 21, 21a are arranged in the range between the strip and the periphery of the brushes, by which nozzles the contact area between the brushes and the surface of the strip is flushed by jets of water under pressure directed substantially tangentially to the periphery of the brushes. By these pressure water jets an improved brushing effect and a continuous cleaning of the rotating brushes 19, 20 from particles of scale are attained. The spraying nozzles 21 and 21a respectively are, in the form of construction illustrated in FIGS. 1 to 3, connected to the same pressure water feeding conduits 18, 18a as the connecting conduits 14, 14a of the guide bars 3, 3a or the connecting conduits 17, 17a of the spraying devices 16, 16a. As the pressure of the water fed through the nozzles 21, 21a may be considerably lower than that of the water fed in the region of the guide bars 3, 3a and through the spraying devices 16, 16a, the nozzles 21, 21a are connected to feed conduits 22, 22a provided with throttle devices. Furthermore, independently adjustable throttle devices can also be arranged in the connection conduits 14, 14a and 17, 17a in order to enable the pressure and/or the quantity of water fed in the region of the guide bars 3, 3a and through the spraying devices 16, 16a to be regulated independently of each other. For the nozzles 21, 21a, however, a separate water feed conduit under lower pressure can also be provided.

In the form of construction illustrated by way of example in FIG. 1, a brush is arranged beyond each spraying device 16, 16a. In cases where exceptionally exigent requirements are placed on the surface condition of the strips, -it is evident that two or more brushes 19 or 20 can be provided which are connected up in series. Furthermore, dry-operating brushes can also be provided instead of or in addition to the wet-operating brushes for polishing the strips. It is likewise possible to dry the descaled wet bands in a drying device, for example a continuous heating furnace, so as to avoid the formation of rust.

In order to improve the descaling elfect, fine abrasives, such as corundum powder, steel turnings or the like, can

be added to the water fed onto the surface of the strip in the region of the guide bars 3, 3a and/ or through the spraying devices 16, 16a. In such cases, it is advisable to make the nozzles of the guide bars 3, 3a as well as those of the distributor pipes 30, 30a and the spraying devices 16, 16a from wear-resistant and abrasion-proof material. In some cases, it will also be advisable to add to the water anti-corrosion agents so as to prevent the formation of rust during the descaling of strip iron.

' The invention may be embodied in other specific forms Without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

I claim:

1. In an apparatus for descaling strip material, in combination, means for guiding strip material along a selected path; and bending means located along said path for bending said strip material during passage along said path, said bending means including two curved and converging bending surface portions merging in an apex surface portion adapted to engage a surface of the strip material and said bending means including a plurality of nozzle means respectively communicating with said apex surface portion by means of outlet opening flaring in direction transverse to said path toward said apex surface portion for directing liquid under pressure between said surface of the strip material and said bending surface to build a layer of pressure liquid betwen said surfaces on which the strip material glides so as to reduce friction between said surfaces.

2. An arrangement as defined in claim 1 in which adjacent flaring outlet openings merge with each other.

3. In an apparatus for descaling strip material, in combination, means for guiding strip material along a selected path; bending means located along said path for bending said strip material during passage along said path, said bending means including a support, a pair of complementary bending members removably mounted on said support and having each a bending surface curved in direction of said path and meeting the bending surface of the other bending member in an apex surface portion adapted to engage a surface of the strip material; passage means formed in said support and in said bending members and opening into said apex surface portion for directing liquid under pressure between said surface of the strip material and said apex surface portion to build a layer of pressure liquid between said surfaces on which the strip material glides so as to reduce friction between said surfaces; and means for removably fastening said bending members to said support.

4. In an apparatus for descaling strip material, in combination, means for guiding strip material along a selected path; and bending means located along said path for bending said strip material during passage along said path, said bending means including two curved and converging bending surface portions each merging in an apex surface portion adapted to engage a surface of the strip material; a plurality of elongated pressure chambers formed in said bending means extending spaced from and aligned with each other transverse to said path substantially through a width equal to that of the strip material and being open toward the crest of said bending surface; and passage means including a distributor passage of relatively large cross section and extending transverse to said path through said bending means. and a plurality of short passages spaced from each other along the length of said distributor passage and communicating with opposite ends thereof with the latter and said elongated pressure chambers, respectively, for directing liquid. under sufficient contin- 7 s uous pressure between said apex surface and the surface References Cited by the Examiner of said strip material to build and'maintain a layer of UNITED STATES PATENTS liquid between said surfaces on which the strip material 401 208 5/89 pp 205 26 illllf fisclsljld thereby to prevent dlrect contact between said 5 1:170:209 2/16 Wood 270-6 5. An arrangement as defined in claim 4 and including 323 32 t k y v a plurall y of Channels Open toward said bending surface 2,984,398 5/61 Chalmers 95 and being aligned with said pressure chambers, said channels having a depth substantially smaller than that of said chambers and extending respectively between said charn- 10 CHARLES WILLMUTH P'lmary Exammer bers and adjacent ends of chambers and bending means. JOSEPH BEIN, WALTER SCHEEL, Examiners- 

1. IN ANA APPARATUS FOR DESCALING STRIP MATERIAL, IN COMBINATION, MEANS FOR GUIDING STRIP MATERIAL ALONG A SELECTOR PATH; AND BENDING MEANS LOCATED ALONG SAID PATH FOR BENDING SAID STRIP MATERIAL DURING PASSAGE ALONG SAID PATH, SAID BENDING MEANS INCLUDING TWO CURVED AND CONVERGING BENDING SURFACE PORTIONS MERGING IN AN APEX SURFACE PORTION ADAPTED TO ENGAGE A SURFACE OF THE STRIP MATERIAL AND SAID BENDING MEANS INCLUDING A PLURALITY OF NOZZLE MEANS RESPECTIVELY COMMUNICATING WITH SAID APEX SURFACE PORTION BY MEANS OF OUTLET OPENING FLARING IN DIRECTION TRANSVERSE TO SAID PATH TOWARD SAID APEX SURFACE PORTION FOR DIRECTING LIQUID UNDER PRESSURE BETWEEN SAID SURFACCE OF THE STRIP MATERIAL AND SAID BENDING SURFACE TO BUILD A LAYER OF PRESSURE LIQUID BETWEEN SAID SURFACES ON WHICH THE STRIP MATERIAL GLIDES SO AS TO REDUCE FRICTION BETWEEN SAID SURFACES. 